Compost-enhanced humification of organic pollutants: Mechanisms, challenges, and opportunities

Organic pollutants remain a persistent threat to ecosystems and human health. In soils, humification gradually converts these compounds into stable humic substances and attenuates their toxicity, but the transformation can take decades-far too slow to match current pollution loads. In this Perspective, we argue that mature compost offers a pragmatic means to accelerate this process: it delivers partially humified intermediates that can "seed" soil humification and shorten its timescale from decades to seasons. Spectroscopic evidence shows that compost-derived humus is enriched in aromatic backbones and reactive functional groups (-COOH, -OH) that both catalyze further condensation of organic matter and immobilise pollutants through π-π stacking, hydrogen bonding and covalent coupling. By merging these catalytic and sorptive functions, compost amendments provide a scalable, low-cost route to the long-term stabilization of organic contaminants. We outline the key mechanistic questions that now need resolution-particularly the reactivity of specific intermediates in situ-to guide field trials and unlock the full potential of compost-driven accelerated humification as an environmental remediation platform.